The tragic death of a South Carolina 10-year-old more than an hour after he had gone swimming has focused a spotlight on the little-known phenomenon called “dry drowning” — and warning signs that every parent should be aware of.

“I’ve never known a child could walk around, talk, speak and their lungs be filled with water,” Cassandra Jackson told NBC News in a story broadcast Thursday on TODAY.

On Sunday, Jackson had taken her son, Johnny, to a pool near their home in Goose Creek, S.C. It was the first time he’d ever gone swimming — and, tragically, it would be his last.

At some point during his swim, Johnny got some water in his lungs. He didn’t show any immediate signs of respiratory distress, but the boy had an accident in the pool and soiled himself. Still, Johnny, his sister and their mother walked home together.

“We physically walked home. He walked with me,” Jackson said, still trying to understand how her son could have died. “I bathed him, and he told me that he was sleepy.”

Spongy materialLater, she went into his room to check on him. “I walked over to the bed, and his face was literally covered with this spongy white material,” she said. “And I screamed.”

A family friend, Christine Meekins, was visiting and went to see what was wrong. “I pulled his arm and said, ‘Johnny! Johnny!’ ” Meekins told NBC. “There was no response. I opened one of his eyes and I just knew inside my heart that it was something really bad.”

Johnny was rushed to a local hospital, but it was too late. Johnny had drowned, long after he got out of the swimming pool.

According to the Centers for Disease Control, some 3,600 people drowned in 2005, the most recent year for which there are statistics. Some 10 to 15 percent of those deaths was classified as “dry drowning,” which can occur up to 24 hours after a small amount of water gets into the lungs. In children, that can happen during a bath.

Dr. Daniel Rauch, a pediatrician from New York University Langone Medical Center, told TODAY’s Meredith Vieira that there are warning signs that every parent should be aware of. Johnny Jackson exhibited some of them, but unless a parent knows what to look for, they are easily overlooked or misinterpreted.

The three important signs, he said, are difficulty breathing, extreme tiredness and changes in behavior. All are the result of reduced oxygen flow to the brain.

Johnny had two of those signs — he was very tired when he got home, and he had had the accident in the pool. But like most parents, Cassandra Jackson had no idea this could be related to water in his lungs.

Delayed reactionRauch said that the phenomenon of dry drowning is not completely understood. But medical researchers say that in some people, a small amount of inhaled water can have a delayed-reaction effect.

“It can take a while for the process to occur and to set in and cause difficulties,” Rauch said. “Because it is a lung process, difficulty breathing is the first sign that you would be worried about.”

The second sign is extreme fatigue, which isn’t always easy to spot. “It’s very difficult to tell when your child is abnormally tired versus normal tired after a hot day and running around in the pool,” Rauch said. “The job of the lungs is to get oxygen into the blood and your brain needs oxygen to keep working, so when your brain isn’t getting oxygen, it can start doing funny things. One of them is becoming excessively tired, losing consciousness and the inability to be aroused appropriately.”

Finally, there are changes in behavior, Rauch said — another tough call when dealing with very small children, whose moods and behavior can change from one minute to the next.

“Another response of the brain to not getting oxygen is to do different things,” Rauch explained, saying parents should be concerned “if your child’s abnormally cranky, abnormally combative — any dramatic change from their normal pattern.”

He admitted, “It is very difficult to pick this up sometimes.” But spotting the warning signs and getting a suspected victim to an emergency room can save a life, he added.

Victims of dry drowning are treated by having a breathing tube inserted so that oxygen can be supplied under pressure to the lungs. “Then we just wait for the lung to heal itself,” he said.

But for Cassandra Jackson, it’s knowledge gained too late. She and Meekins sat in her home, looking at pictures of the bright and happy son who was no more.

“He was very loving, full of life,” the grieving mother said. “That was my little man.”(Source from: http://today.msnbc.msn.com/id/24982210/)

What is dry drowning?Dry drowning is basically drowning without water. With dry drowning, you are not drowning from an immediate immersion in water; it is more of a delayed effect of a small amount of water in the lungs. This can result in laryngospasms, which minimize the amount of water aspirated into the lungs. Respiratory arrest may follow, leading to an inadequate supply of oxygen in the blood, cardiac arrest, and eventually brain death.

Several other mechanisms can cause dry drowning, including acute respiratory distress syndrome (ARDS), which is an acute, severe injury to most or all of both lungs or electrolyte abnormalities resulting from a dilution of the blood after aspirated water is absorbed into the blood, leading to heart rhythm abnormalities.

How long after an incident is there a risk for dry drowning?Dry drowning usually occurs between one hour and 24 hours after an incident. A person can have a drowning incident, be pulled out of the water, be OK, and then sometime within the next 24 hours, they can dry drown.

Are there any risk factors for dry drowning?Yes, there are risk factors and situations in which dry drowning may be more likely, such as if the child is not a good swimmer or a first-time swimmer. Children and adults with underlying lung problems such as asthma may also be at increased risk for dry drowning. To prevent an incident, use common sense and never let inexperienced swimmers in the pool without a lot of supervision.

Is dry drowning rare?Drowning is a huge problem. About 4,000 people drown each year and 1,400 of these are children. The CDC has no statistics on the number of dry drowning deaths.

Are there any red flags that suggest a person is at risk for dry drowning?Yes, there are some signs that a person may have a dry-drowning episode. They include persistent coughing, shortness of breath, or pain in chest. All of those things are signals that something could be wrong. If someone comes out of the water and coughs for a minute, then calms down -- that is much different than if the child keeps coughing or complaining of pain. Like the child involved in the incident in South Carolina, a change in mental status and/or lethargy may also indicate that something is wrong.

What should you do if you think a child is at risk?This is not something that can be handled by a parent. Call a doctor or bring the child to an emergency room if there are signs of dry drowning following a near-drowning incident.

Can dry drowning be treated?Yes. If it is caught early, dry drowning can be treated. The treatment involves supplying oxygen to the lungs and getting the breathing process restarted.(Source from: http://children.webmd.com/news/20080605/sc-dry-drowning-death-draws-attention)